This invention generally relates to a surgical instrument assembly for use in cutting and retrieving objects from internal body cavities and, more specifically, to a surgical instrument assembly for use in snare cauterization procedures. The present invention also relates to a method for cutting and retrieving objects from internal body cavities and, in a preferred form, to a method for cutting, capturing and/or retrieving polyps and other aggregates of organic tissue from a patient""s internal organs via a snare cauterization procedure.
A wire snare has been used in many different configurations and for many different medical uses. The snare, when equipped for use with cautery, has been used for polypectomies. For example, during a colonoscopy, or other endoscopic procedures, a wire loop or snare, combined with cautery, is frequently used to biopsy or excise lesions. While a wire loop or snare is very effective at cutting free a lesion, it has substantially no ability to capture and/or retrieve the excised lesion.
Typically, a second instrument is used to retrieve the excised lesion. The second instrument most often is provided in the form of a wire basket having several loops angularly offset and preferably, but not necessarily, perpendicular to each other in the case of two loops and designed to trap the excised lesion, such as a stone basket used in urology and gastroenterology. The use of two different instruments, one instrument to cut and a second instrument to retrieve, however, is inconvenient, inefficient, time consuming and can sometimes lead to the loss of the excised lesion.
What is still desired is a single instrument that can snare and retrieve a lesion. Preferably, the instrument will be simple in design and reliable in use, and will allow repeated use of a snare or a retrieval configuration, as required, by simple mechanical means.
The present invention provides a simple, but elegant solution to this problem by providing a device for selectively capturing, cutting and retrieving tissue, wherein the device includes a cutting snare, or cauterization wires, that can be incorporated into a retrieval basket configuration also including a basket snare, or basket wires, without removing the cutting snare from a patient""s body. It also allows repeated use of the basket or the snare configuration, as required, by simple mechanical means.
According to one aspect of the present invention, the device includes a handle having an elongated, flexible tube extending therefrom along a central axis to a distal end, a first set of elongated, flexible wires slidingly positioned within the tube and extending along the central axis from the handle to distal ends for extending out of the distal end of the tube, a control tip secured to the distal ends of the first set of wires, the control tip having a slot, and a second set of elongated, flexible wires slidingly positioned within the tube and extending along the central axis from the handle, through the slot in the control tip, to distal ends, the second set of wires being coupled at the distal ends. A retaining pin is secured to the control tip and extends transversely through the slot of the control tip and between the second set of wires. The retaining pin allows the coupled distal ends of the second set of wires to be extended from the control tip, and prevents the coupled distal ends of the second set of wires from being withdrawn from the slot of the control tip and into the tube. In addition, the retaining pin drives the coupled distal ends of the second set of wires from the distal end of the tube upon the distal ends of the first set of wires being driven from the distal end of the tube.
According to one aspect of the present invention, the first and second sets of wires have a preset shape, preferably curving in an arc near their distal ends, so that when within the tube, the wires are substantially coaxial with the tube, but when extended from the tube, their distal ends form a loop.
According to an additional aspect of the present invention, the control tip is a discrete element that is secured to the first set of wires and the slot of the control tip is oriented such that a first reference plane formed by the loops of at least two of the wires of the first set and a second reference plane formed by the loops of at least two of the wires of the second set are angularly offset. According to a further aspect, the first reference plane is substantially perpendicular to the second reference plane.
According to still another aspect of the present invention, the first set of wires includes only two wires. According to an additional aspect, the second set of wires includes only two wires.
According to another aspect of the present invention, two single wires with distal ends bent to form loops are provided to be used to cut and retrieve tissue instead of two sets of wires. Preferably, the wire includes a front portion with an expanded distal end and a rear portion with an expanded proximal end. The distal end of the front portion and the proximal end of the rear portion are joined by a tube with crimped ends, wherein the front portion and the rear portion are relatively rotatable with each other.
According to another aspect of the present invention, the first set of wires of the device is formed by a single continuing wire folded at a distal end, instead of two wires connected to a discrete contral tip. The distal end of the continuing retrieving wire forms a xe2x80x9ccontrol tipxe2x80x9d, preferably an xe2x80x9cSxe2x80x9d or xe2x80x9c8-likexe2x80x9d shape structure having two apertures and one effective retaining pin portion in the middle. Two wires of the second set of wires (cutting wires) are joined at a distal end and are slidingly positioned within the tube, extending along the central axis from the handle, and wherein each wire of the set passes through one of the two apertures of the control tip. The distal end of the cutting wires is retained by the retaining pin. The xe2x80x9cSxe2x80x9d or xe2x80x9c8-likexe2x80x9d shape control tip replaces the discrete control tip of the previously described embodiment, functioning as a retaining pin for retaining the cutting wires, and also as a bottom a xe2x80x9cbasketxe2x80x9d formed by the retrieving wires and the cutting wires, used to retrieve tissues.
According to a further aspect of the present invention, the device includes a first deployment assembly operatively connected to the first set of wires and allowing a user to selectively extend and withdraw the distal ends of the first set of wires from the distal end of the tube, and a second deployment assembly operatively connected to the second set of wires and allowing a user to selectively extend and withdraw the distal ends of the second set of wires from the distal end of the tube. According to another aspect, a latching mechanism is provided for connecting the first and second deployment assemblies. In accordance with an additional aspect, a locking mechanism is provided for preventing movement of the first deployment assembly.
According to another aspect of the present invention, the handle of the present invention includes an elongated shaft extending along a central axis, a tube connected to a distal end of the shaft, a first sleeve member disposed over the shaft and a second sleeve member disposed over the shaft. The shaft has a front portion, rear portion, and a central portion. The shaft defines an elongated slot through the central portion and an interior channel through the rear portion. The tube connects to and extends from a distal end of the interior channel and forms a elongated continuing passageway with the slot and the interior channel of the shaft for the two sets of wires to pass through. The first set of wires is attached to a first terminal lock which extends from an inner surface of the first sleeve member into the slot of the shaft. The second set of wires is attached to a second terminal lock which extends from an inner surface of the second sleeve member into the slot. Preferably, the second terminal lock defines a slot in a central portion of the second terminal lock for allowing the first set of wires to pass through. The handle also includes a first latch mechanism connected to a proximal end of the first sleeve member and the front portion of the shaft, and a second latch mechanism connected to a distal end of the first sleeve member and a proximal end of the second sleeve member.
During operation, when the device is used for cutting tissue, the first sleeve member with the first set of wires is locked to the shaft by the first latch mechanism and the second sleeve member is released and movable along the shaft. The second set of wires which is attached to the second terminal lock of the second sleeve member is moved with the second sleeve member, and the distal ends of the second set of wires are extended and withdrawn to cut tissue captured by the wires. When the device is used in retrieving excised lesion or tissue, the first latch mechanism is released, and the first sleeve member and the second sleeve member are locked together by the second latch mechanism. The first sleeve member and the second sleeve member with the two sets of wires attached are moved as a unit along the shaft and work as a retrieving tool.
According to another aspect of the present invention, the first sleeve member includes a bearing member and a ring roatatably retained on the bearing member. The ring defines a second slot adapted for engaging with a pin member extending from the second sleeve member. The slot and the pin member constitute the second latch mechanism connecting with the first sleeve member and the second sleeve member. An operator may selectively lock the first sleeve member with the second sleeve member or release the latch mechanism by rotating the ring, and as the same time keep the bearing stationary with respect to the shaft.
According to still another aspect of the present invention, the device comprises a latch mechanism which includes a hook mounted on the first sleeve member by pivot, a first pin member mounted on the shaft, and a second pin member mounted on the second sleeve member. Preferably, the hook has a substantially xe2x80x9cW-likexe2x80x9d shape with two arms extending from a central portion. The hook may selectively lock the first sleeve member with the shaft by engaging with the first pin member on the shaft, or lock the first sleeve member with the second sleeve member by engaging with the second pin member on the second sleeve member. The two arms of the hook are sized such that the hook may only catch one pin at a time. Each arm of the hook has a relatively small protrusion extending inwardly from the distal end of the arm, so that the hook may maintain on the pin when it engages with the pin.
The present invention also provides a method for selectively capturing, cutting and retrieving tissue in a body cavity using a device as defined above. The method includes inserting into the body cavity the distal end of the elongated, flexible tube, and manipulating the second set of wires from the handle so that distal ends of the second set extend from the distal end of the tube and capture tissue to be cut between at least two wires of the second set. A cauterizing current is then applied to the second set of wires such that the tissue is cut, and the first set of wires is manipulated from the handle so that the distal ends of the first set of wires and the control tip extend from the distal end of the tube and capture the cut tissue between the first and the second sets of wires. The distal end of the tube, together with the first and the second sets of wires and the cut and captured tissue, is subsequently withdrawn from the body cavity.
A monopolar RF electrocautery is used in one preferred embodiment. RF energy is applied to the cutting wires at proximal ends of the cutting wires from an external source. Ground conductor is appropriately positioned external to the patient.
These and other features and benefits of the presently disclosed device and method will become more apparent upon reading the following specification in combination with the accompanying drawing figures.